Joyetech Batpack is incredibly simple and convenient to use and now with ECO technology. ECO Tech still provides the best vaping experience but allows the battery to have a very low output. This extends the battery life by almost double. This is the first vaporizer using the AA batteries as the power. Thanks to the exclusive Joyetech ECO technology, you're estimated to achieve approximately 800 puffs with two fully charged Avatar AA Ni-MH batteries (2000mAh). Meanwhile, you can still get around 150 puffs with two disposable normal AA batteries.